ML150 G2 SATA RAID5 - stripe size

[Simon Tims]

Hi all

I've just fitted a new ML150 G2 with the HP 6 port SATA RAID card, and five 80Gb SATA drives.

One drive is a hot spare, the other 4 are for a RAID5 array.

All is well, I built the array using the rom utility, but the stripe size is 256Kb. This seems a bit big! Could I have accidentally changed it and should the default be 64, or is that size normal for a setup like this?

Thanks


Simon

[Jos de Ruiter]

HI,

Do you have light on your disks??
Power or access?

Groetjes,
Jos

[Simon Tims]

Yes, all lights fine and the array works great - it's just the stripe size I'm looking at...

Simon

[Vincent Fleming · Accepted solution]

According to the manual, http://h20000.www2.hp.com/bc/docs/support/SupportManual/c00474317/c00474317.pdf

The default is 64KB.

However, 256KB is not a bad stripe size - it really depends on what kind of load you will be putting on the RAID.

It is typical that larger stripe sizes produce better sequential performance, and smaller stripe sizes are better with databases.

So, if you are going to put a database on the RAID, you probably want to reduce your stripe size. I wouldn't suggest using anything smaller than 64KB, though, as the smaller stripe sizes make for much more overhead for the RAID controller in both normal I/O processing and during rebuilds.

Good luck,

Vince

[Simon Tims]

Thanks Vince.

I deleted the array and remade it to check - the default was 256 so in the end I left it at that.

Server 2003 now installed (just Enterprise evaluation version for testing at present), all seems well (except for short freezes whenever I change anything in Active Directory but hopefully I'll sort that out later!)

Thanks again.

Simon